Hello Ludovic, On Friday 27 March 2015, 11:11:52 wrote Ludovic Desroches: > On Fri, Mar 20, 2015 at 08:12:00PM +0100, Alexander Stein wrote: > > This adds the callback for set_multiple. > > As this controller has a separate set and clear register, we can't write > > directly to PIO_ODSR as this would required a cached variable and would > > race with at91_gpio_set. > > So build masks for the PIO_SODR and PIO_CODR registers and write them > > together. > > Sure seems safer and easier to use SODR and CODR. > > > > > Signed-off-by: Alexander Stein <[email protected]> > Acked-by: Ludovic Desroches <[email protected]> > > A question below. > > > --- > > This was tested by using an own test driver which uses > > gpiod_set_array_cansleep to set multiple GPIOs at once. > > > > drivers/pinctrl/pinctrl-at91.c | 28 ++++++++++++++++++++++++++++ > > 1 file changed, 28 insertions(+) > > > > diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c > > index f4cd0b9..a882523 100644 > > --- a/drivers/pinctrl/pinctrl-at91.c > > +++ b/drivers/pinctrl/pinctrl-at91.c > > @@ -1330,6 +1330,33 @@ static void at91_gpio_set(struct gpio_chip *chip, > > unsigned offset, > > writel_relaxed(mask, pio + (val ? PIO_SODR : PIO_CODR)); > > } > > > > +static void at91_gpio_set_multiple(struct gpio_chip *chip, > > + unsigned long *mask, unsigned long *bits) > > +{ > > + struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip); > > + void __iomem *pio = at91_gpio->regbase; > > + unsigned long set_mask; > > + unsigned long clear_mask; > > + size_t i; > > + > > + set_mask = 0; > > + clear_mask = 0; > > + > > + for (i = 0; i < chip->ngpio; i++) { > > + if (*mask == 0) > > + break; > > + if (__test_and_clear_bit(i, mask)) { > > For my knowledge, why do you need to clear the mask?
I tried to do the same as mpc8xxx_gpio_set_multiple. I think the reason is that an empty mask will quit that loop potentially earlier. Best regards, Alexander -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
